it was a trailer for the imax showing in some theaters, did they add it to the blue ray too for a promotional, the dkr hasn't come out yet and Nolan could reach many more people if it was added to this dvd release.
Yeah, I was surprised DKR prologue was attached to MI4 and not Sherlock Holmes, but, I think it was definately more an IMAX thing than anything else, and a lot of people saw (and enjoyed MI4 because the news didn't hit home to all that the DKR prologue was only in some theaters (like 15 or so) and not all IMAX screens, so we saw MI4 mostly for DKR which never appeared. But this is definately the best MI movie by far. (PS I drove 5 hours JUST to see DKR prologue in IMAX twice). The Prologue fyi is the first 6 minutes of the DKR movie.